With the development of electronic devices such as smart phone and smart watch, which are provided with a touch screen, various manufacturers are scrambled to launch differentiated devices, hoping to attract consumers. A highlight design emerged in the current market is that, the housing of the electronic device is configured to have a curved housing, i.e. the surface of the housing is no longer a flat surface, but a 3D stereoscopic curved surface. The electronic device having a curved housing can fit the hand of the user better, providing a comfortable sensation for holding and handling the electronic device. If the watch housing is configured to be a curved housing, it can fit the wrist of the user better, providing a comfortable sensation for wearing the watch. Furthermore, when a display housing having the curved configuration, the displaying content displayed on the display can have an intense stereoscopic impression, and a perception can thereby be improved. Because glass has a better tactile sensation, when it serves as the materials of the housing of the electronic device, the electronic device meets a great favor. The traditional method for attaching a decorative film to the planar glass is a rolling processing method or a gas bag processing method. However, the method cannot be applied to attach a decorative film to a 3D glass. Aforementioned processing method causes a wrinkle of the decorative film on the surface edges of the 3D glass, thereby affecting the processing effect of the 3D glass.